Electric lamp

ABSTRACT

The invention relates to an electric lamp, more particularly to a lamp for motor vehicle, the cap of which is provided with a metal support sleeve (53) constructed in the shape of a ring and at least one pressure spring (1) for securing the lamp in the lampholder. The at least one pressure spring (1) is constructed as a cambered leaf spring whose ends (11, 12) bear against the inner wall of the support sleeve and which has a V-shaped region (100) which reaches through a cutout (53b) in the support sleeve (53).

TECHNICAL FIELD

The invention relates to electric lamps and particularly to electriclamp mountings. More particularly the invention is concerned with a lampmounting with a spring.

BACKGROUND ART

Such an electric lamp is described, for example, in Patent ApplicationPCT/DE96/01982. This patent application describes a cementlessly cappedelectric lamp for use in a motor vehicle headlight. This lamp has a lampcap constructed from metal parts and plastic parts. The lamp cap has ametal holding part in which the lamp bulb is fixed, a metal supportsleeve supporting the holding part, and a plastic cap part, which isprovided with the electric terminals of the lamp and in which thesupport sleeve is anchored. The metal support sleeve of the lamp isconstructed in the shape of a ring and matched to the fitting diameterof the opening, constructed as a lampholder, of the headlight reflector,and equipped with at least one pressure spring which, after the lamp hasbeen installed in the reflector, bears against the reflector wall in theregion of the lamp holder. This at least one pressure spring ensures thelamp is firmly seated in the lampholder of the reflector, and balancesslight tolerances in the manufacture of the lamp cap and in the opening,constructed as lampholder, of the headlight reflector. The at least onepressure spring is designed as a cambered leaf spring whose ends bearagainst the inner wall of the metal, ring-shaped support sleeve.Moreover, the at least one leaf spring has an outwardly cambered sectionwhich reaches through a cutout in the support sleeve and, after the lamphas been installed in the reflector, bears against the reflector wall inthe region of the lampholder, as well as two inwardly cambered sections,which are arranged on both sides of the outwardly cambered section ofthe leaf spring.

DISCLOSURE OF THE INVENTION

In the electric lamp according to the invention, the lamp cap is fittedwith at least one pressure spring which, after the lamp has beeninstalled in the headlight reflector, bears against the reflector wallin the region of the lampholder and ensures that the lamp is seatedfirmly in the lampholder of the reflector. The pressure spring isconstructed as a cambered leaf spring. It has an outwardly camberedsection, which reaches through a cutout in the support sleeve and, afterthe lamp has been installed in the headlight reflector, bears againstthe reflector wall, and which is provided according to the inventionwith a V-shaped region. At least the connecting piece connecting the twoV limbs reaches through the cutout in the support sleeve, with theresult that, after the lamp has been installed in the headlightreflector, it bears resiliently against the reflector wall constructedas the lampholder. The spring action of the pressure spring is improvedby comparison with the prior art quoted above by means of the V-shapedregion. The V-shaped region of the outwardly cambered section reducesthe contact area between the lampholder and the pressure spring bycomparison with the prior art, and increases the contact pressure. Inthis case, the angle which the two V limbs of the V-shaped region formwith one another is advantageously selected such that it is between 80degrees and 110 degrees. In order to avoid scratch traces on thelampholder when assembling the lamp in the headlight, the connectingpiece connecting the two V limbs is advantageously rounded. The twoinwardly cambered sections of the leaf spring are advantageouslyconstructed in the shape of a U. As a result, by comparison with theprior art the pressure acting on the leaf spring after the lamp has beenmounted can be better absorbed by a reversible deformation of theinwardly cambered sections, that is to say by a reversible compressionof the U-shaped sections of the leaf spring.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below with the aid of apreferred exemplary embodiment. In the drawing:

FIG. 1 shows a diagrammatic side view of an electric lamp according tothe invention,

FIG. 2 shows a top view of the plastic cap part and the metal supportsleeve, injected therein, of the electric lamp illustrated in FIG. 1,and

FIG. 3 shows a side view of the pressure spring according to theinvention.

FIG. 4 shows a cross sectional view of the plastic cap part and thepressure spring

BEST MODE FOR CARRYING OUT THE INVENTION

In the preferred exemplary embodiment of the electric lamp according tothe invention, it is a single-filament halogen lamp which is providedfor use in a motor vehicle headlight. This lamp has an essentiallycylindrical glass lamp bulb 50 with a tightly pinched end 50a which istermed the pinched foot 50a. The dome 50b of the lamp bulb 50 isprovided with a black, light-absorbing coating. The light source is anincandescent filament 50c, which is aligned parallel to the lamp bulbaxis and is connected in an electrically conducting fashion to lead-inwires 51 brought out of the pinched foot 50a. The lamp bulb 50 is fixedwith its pinched foot 50a in a metal holding part 52 constructed as afixing ring. The fixing ring 52 is supported by a metal intermediatering 58, which is equipped with three integrally formed, angled-awaywelding lugs 58a. For its part, the intermediate ring 58 is welded to ametal support sleeve 53 by LASER. In addition to the metal fixing ring52, the intermediate ring 58 and the metal support sleeve 53, the lampcap also has a plastic cap part 54, which is provided with the electricterminals 55 of the lamp and in which the support sleeve 53 is anchored.The electric terminals 55 of the lamp are respectively welded to one ofthe lead-in wires 51. The plastic cap part 54 is an injection-mouldedpart into which the metal support sleeve 53 is injected.

The support sleeve 53 has three integrally formed reference noses 53a,which are arranged equidistantly along a circular circumference and areused to adjust the incandescent filament 50c and to fasten the lamp inthe reflector (not illustrated) of the headlight. The reference noses53a are angled away from the support sleeve 53 and lie in a commonplane. The welding lugs 58a of the intermediate ring 58 are welded tothese reference noses 53a by LASER. The intermediate ring 58 offersadditional possibilities of adjustment in the reference plane defined bythe reference noses 53a.

The plastic cap part 54 has a circumferential, conically designed groove54b which is in the shape of a ring and in which a sealing ring (notillustrated) made from rubber or silicon is arranged. The sealing ringbears against the outside of the reflector wall and seals the opening,constructed as lampholder, of the reflector. The inside diameter of thesealing ring is matched true to size to the conically designed groove54b, and varies linearly with the height of the sealing ring. A camberedleaf spring 1 (FIG. 3), which serves to fasten the lamp in theheadlight, projects through a cutout 53b, arranged below one of thethree reference noses 53a, in the wall of the support sleeve 53 in theshape of a ring. The ends 11, 12 of the leaf spring 1 bear against theinner wall of the support sleeve 53 and against in each case one stop59a, 59b constructed in one piece with the plastic cap part 54, with theresult that the leaf spring 1 is fixed clamped between these two stops59a, 59b designed as a holder.

The three reference noses 53a, the sealing ring arranged in the groove54b, and the pressure spring 1 serve to fasten the lamp in thelampholder of the headlight reflector. The lamp cap and the lampholderform a bayonet catch. In order to install the lamp in the reflector, thelamp is inserted, with the lamp bulb 50 in front, into the opening,constructed as lampholder, of the reflector, the three reference noses53a respectively reaching through a true-to-size recess in the edge ofthe opening. Thereafter, the lamp is turned in the lampholder as far asa stop, with the result that the reflector wall is arranged seatedclamped between the reference noses 53a and the sealing ring. Thepressure spring 1 bears resiliently against the edge of the opening,constructed as lampholder, of the reflector. In order to prevent thelamp from being erroneously installed in the reflector, all threereference noses 53a are of different shape. The same also holds, ofcourse, for the recesses, matched to the reference noses 53a, in theopening constructed as lampholder. Details of the pressure spring 1 arerepresented in FIG. 3.

The pressure spring 1 is constructed as a cambered leaf spring. It hastwo slightly curved ends 11, 12 which, after they are mounted, bearagainst the inner wall of the support sleeve 53 in the shape of a ring.Moreover, two stops 59a, 59b which are designed in one piece with theplastic cap part 54 and against which the ends 11, 12 abut are used tofix the leaf spring 1. The leaf spring 1 is thereby held clamped betweenthese stops 59a, 59b (FIG. 10). It has an outwardly cambered section 10with a V-shaped region 100 which, after the leaf spring 1 has beenmounted, reaches through the cutout 53b in the support sleeve 53 and,after the lamp has been installed in the headlight bears in a clampedfashion against the reflector opening constructed as lampholder. The Vlimbs 101, 102 of the V-shaped region 100 form an angle of approximately96 degrees with one another and are connected to one another by arounded connecting piece 103. The cutout 53b is represented in the topview of FIG. 2 only with dashed lines, since it is covered by one of thereference noses 53a. The outwardly cambered section 10 of the leafspring 1 is respectively connected by means of two inwardly cambered,U-shaped sections 13 or 14 to one of the leaf spring ends 11 or 12. Theleaf spring 1 consists of a spring steel sheet of 0.25 mm thickness. Thereference numeral 60 in FIG. 2 denotes the bushings for the lead-inwires 51 of the lamp in the plastic cap part 54.

FIG. 4 shows a cross sectional view of the plastic cap part and thepressure spring. The electric lamp is seen to have a lamp cap which hasa metal holding part (52) in which the bulb (50) of the lamp is fixed.The lamp cap has a metal support sleeve (53), connected to the metalholding part (52), and a plastic cap part (54), which is provided withelectric terminals (55) of the lamp in which the metal support sleeve(53) is anchored. The metal support sleeve (53) is constructed in theshape of a ring and has a cutout (53b). The lamp cap is fitted with atleast one pressure spring (1). The pressure spring (1) is constructed asa cambered leaf spring. The ends (11, 12) of the leaf spring (1) bearagainst the inner wall of the support sleeve (53). The leaf spring (1)has an outwardly cambered section (10) which reaches through the cutout(53b). The leaf spring (1) has two inwardly cambered sections (13, 14)which respectively connect the outwardly cambered section (10) to one ofthe leaf spring ends (11, 12). The outwardly cambered section (10) ofthe leaf spring (1) has a region (100) constructed in the shape of a V.At least the connecting piece (103) which connects the two limbs (101,102) of the V-shaped region (10) reaches through the cutout (53b) in thesupport sleeve (53). it can bee seen that the two V-limbs (101, 102) ofthe V-shaped region (100) of the leaf spring (1) are connected to oneanother via a rounded connecting piece (103). It can be seen that thetwo V-limbs (101, 102) of the leaf spring (1) form with one another anangle of between 80 degrees and 110 degrees. It can be seen that theinwardly cambered sections (13, 14) of the leaf spring, (1) areconstructed in the shape of a U.

What is claimed is:
 1. An electric lamp comprising: a lamp cap which hasa metal holding part (52) in which the bulb (50) of the lamp isfixed,the lamp cap having a metal support sleeve (53), connected to themetal holding part (52), and a plastic cap part (54), which is providedwith electric terminals (55) of the lamp and in which the metal supportsleeve (53) is anchored, the metal support sleeve (53) being constructedin the shape of a ring and having a cutout (53b), the lamp cap beingfitted with at least one pressure spring (1) being constructed as acambered leaf spring, the ends (11, 12) of the leaf spring (1) bearingagainst the inner wall of the support sleeve (53), the at least one leafspring (1) having an outwardly cambered section (10) which reachesthrough the cutout (53b), and the at least one leaf spring (1) havingtwo inwardly cambered sections (13, 14) which respectively connect theoutwardly cambered section (10) to one of the leaf spring ends (11, 12),wherein the outwardly cambered section (10) of the at least one leafspring (1) has a region (100) constructed in the shape of a V, at leastthe connecting piece (103) which connects the two V limbs (101, 102) ofthe V-shaped region (100) reaching through the cutout (53b) in thesupport sleeve (53).
 2. An electric lamp according to claim 1, whereinthe two V-limbs (101, 102) of the V-shaped region (100) of the leafspring (1) are connected to one another via a rounded connecting piece(103).
 3. An electric lamp according to claim 1, wherein the two V-limbs(101, 102) of the leaf spring (1) form with one another an angle ofbetween 80 degrees and 110 degrees.
 4. An electric lamp according toclaim 1, wherein the inwardly cambered sections (13, 14) of the leafspring (1) are constructed in the shape of a U.